The pool water must be clear and totally free of both visible and invisible dirt. Visible dirt is mainly removed by the pool filter. The invisible dirt is made up not only of bacteria, which can multiply very rapidly and cause problems, but also algae and fungi of various kinds which spread to the pool, where they find the conditions pleasant. Chemical agents are used to combat and control these.
To make sure the water in the pool is crystal clear and clean, it needs to be chemically treated for:
The pool water is disinfected to kill organisms such as bacteria, algae and fungi. Pool chemicals “burn off” the contaminants and make the water sparkling and fresh. The most widely used and effective agents are those that contain chlorine or bromine.
Disinfecting agents work at their best within a narrow range of pH. The water must be neither too acid nor too basic. The ideal pH range for the pool and the human body is between 7.2 and 7.6.
Anti-algals prevent the algae from getting established and multiplying in the pool. Algae that have already become established need to be removed with an extra-high dose of chlorine (shock chlorination). With regular chlorination, there is normally no need for anti-algal treatment.
If the pool water is filtered well, smaller amounts of chemicals will be needed to keep the water clean and clear. Flock and clarifier cause the micro-dirt to form larger particles, which are trapped by the filter. Only pools with a sand filter can be flocked.